The present invention relates generally to shear wall constructions, and more particularly to methods and structures for vertically tying fabricated shear wall segments through floor and ceiling structures.
In the construction of buildings, fabricated wall segments are sometimes built separately and erected on site and are sometimes built on site while coordinated with other aspects of building construction. Fabricated shear walls need to be connected not only to each other but also to underlying and overlying structural elements, such as floors and roofs.
With reference to FIG. 1, a building 10 comprising a plurality of wall sections 11 is schematically illustrated in cross-section. During an earthquake, like any other building structural elements, these wall segments are subject to various stresses. Wall segments 12 near building corners, in particular, are subjected to vertical stresses as the central portions of the wall act as a fulcrum. Because these vertical stresses are directed towards horizontal nailing that hold the structures together, corner wall segments 12 are typically referred to as shear walls 12.
In order to resist stresses to which shear walls 12 are subjected, hold-down devices are often provided to connect the vertical portions of a shear wall 12 to other adjacent building structural elements. While conventional hold-down devices, framing configurations and other connection hardware somewhat assist the ability of shear walls to resist seismic stresses, a need exists for further improvement.
In satisfaction of this need, the present invention provides a shear wall construction that includes close laterally-spaced pairs of vertical studs or posts on each lateral side of a shear wall sheet (e.g., plywood). A channel-defining member is fitted between and affixed to the spaced studs. A tie member extends from the channel-defining member into a vertically-adjacent building structural element.
The channel-defining member generally comprises metal or other structural material, and defines a longitudinal channel generally parallel to the studs. In the illustrated embodiments, the member is a generally tubular element, though in other arrangements the member can comprise a generally C- or U-shaped element. The preferred tie member is a threaded rod that extends from an end plate of the channel-defining member and into a concrete foundation or floor. Similar constructions are provided at opposite lateral ends of the shear wall, such that the shear wall can better resist seismic forces.
Additionally, the preferred embodiments provide a bottom track for aiding and reinforcing the vertical connection. In particular, the bottom track comprises two longitudinal flanges with a plurality of fastener holes therein, and a central longitudinal portion having punched-through holes. The punched-through holes provide downwardly extending protrusions.
In operation, the bottom track is positioned over a concrete form with the flared protrusions from the punched-through holes extending downwardly into a region in which a concrete floor will be formed. Similarly, the tie members extend through the track into the concrete form. Concrete is then allowed to harden around the tie member and track protrusions, such that the bottom track is secured to the concrete floor. The shear wall is then erected over the track and flanges are folded up and fixed to sheat the bottom edge of the shear wall.